Rapid evolution of computer display technology has rendered techniques presently used for establishing operating modes of computer display monitors either inefficient or impractical. For example, in IBM Personal System/2 (PS/2).sup.1 systems, driver or application software requiring control of display monitor functions operate whenever activated to: (a) sense a 4-bit monitor identity (ID) function, by examining DC levels existing on 4 monitor ID pins in a standardized connector which links the display monitor to the computer's display adapter, (b) uses this ID information to locate monitor mode data, and (c) uses the monitor mode data to set the currently attached display monitor to a mode suitable for that monitor and the memory capacity of the system. The software operates in this manner each time that it is loaded for execution by the system. Each monitor attachable to the system has the ID pins in its connector uniquely attached to ground and non-ground potentials defining its respective type as one of 15 possible types that could be directly represented by 4 bit functions. In general, the monitor mode data is hardcoded into the software and carried with it through the system. If a new type display monitor is to be supported the software must be revised to incorporate the mode data for that monitor. FNT .sup.1 IBM, Personal System/2 and PS/2 are trademarks of the International Business Machines Corporation.
A problem with this technique is that the connector ID pins as presently used do not allow more than 16 monitor types to be supported, and it is inefficient to consider storage of additional monitor mode data in the software to support new monitor types. At the present rate of introduction of new monitor types, it is becoming apparent that there is likely to be a need for supporting many more than 15 types in the near future. Accordingly, it is becoming necessary to consider how to provide extended support of additional monitor types in a cost effective and efficient manner.
It is recognized that for such extended support to be cost effective and efficient, it should be provided in a manner that is not logically inconsistent with techniques used presently for supporting attachment of presently known monitor types, and should not impose an inequitable burden on developers of new application and/or display driver software, or new display monitor hardware or their connectors. Such support, and any associated hardware and software, should also be "user friendly" so that attachment of a new type display monitor is made simple for users.
The present invention seeks to provide a mechanism and associated method for providing such extended support of additional monitor types, which could be integrated easily into existing systems.